Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980589
J. Deskur, T. Pajchrowski, K. Zawirski
The paper presents the problem of obtaining a good dynamics of the PMSM drive with complex mechanical structure and variable moment of inertia. Proposed approach bases on proper design of feedback filter to reduce influence of mechanical resonance's and applying a neural speed controller trained online, which can adapt itself to variable inertia. As an alternative, robust PI controller with set-point weighting is presented. The results of simulation and experimental investigations show good properties of designed control system.
{"title":"Speed controller for a drive with complex mechanical structure and variable parameters","authors":"J. Deskur, T. Pajchrowski, K. Zawirski","doi":"10.1109/EPEPEMC.2014.6980589","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980589","url":null,"abstract":"The paper presents the problem of obtaining a good dynamics of the PMSM drive with complex mechanical structure and variable moment of inertia. Proposed approach bases on proper design of feedback filter to reduce influence of mechanical resonance's and applying a neural speed controller trained online, which can adapt itself to variable inertia. As an alternative, robust PI controller with set-point weighting is presented. The results of simulation and experimental investigations show good properties of designed control system.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125666218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980553
A. Gencer
Due to the rapid development of technology, the new applications are occurring into presence which request high efficient speed control and high efficient position control. So, travelling wave ultrasonic motors (TWUSM) have been drawn attention as important actuators for position control and speed control applications of late years. The relationship between rotor speed and different load behaviours of the TWUSM is not linear. In order to solve this nonlinearities and variation problems of TWUSM, proportional-integral (PI) controller, proportional integral-derivative (PID) controller, frequency controller and phase difference controller are proposed and implemented for position control and rotor speed control in this study. There are many speed control techniques such as frequency control, applied voltage phase difference control, applied voltage amplitude control. Besides these control techniques increase the efficiency of the system, we required to design control techniques which using TWUSM position control. For this we make use of the control system techniques such as controllers and compensation techniques. The proposed system evaluates the steady-state performance of TWUSM driver system by using PID controller, frequency controller, and phase difference controller. The obtained simulation results of the proposed technique are analyzed and presented with comparisons.
{"title":"A new speed/position control technique for travelling wave ultrasonic motor under different load conditions","authors":"A. Gencer","doi":"10.1109/EPEPEMC.2014.6980553","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980553","url":null,"abstract":"Due to the rapid development of technology, the new applications are occurring into presence which request high efficient speed control and high efficient position control. So, travelling wave ultrasonic motors (TWUSM) have been drawn attention as important actuators for position control and speed control applications of late years. The relationship between rotor speed and different load behaviours of the TWUSM is not linear. In order to solve this nonlinearities and variation problems of TWUSM, proportional-integral (PI) controller, proportional integral-derivative (PID) controller, frequency controller and phase difference controller are proposed and implemented for position control and rotor speed control in this study. There are many speed control techniques such as frequency control, applied voltage phase difference control, applied voltage amplitude control. Besides these control techniques increase the efficiency of the system, we required to design control techniques which using TWUSM position control. For this we make use of the control system techniques such as controllers and compensation techniques. The proposed system evaluates the steady-state performance of TWUSM driver system by using PID controller, frequency controller, and phase difference controller. The obtained simulation results of the proposed technique are analyzed and presented with comparisons.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129675301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980619
D. Kouchih, R. Hachelaf, N. Boumalha, M. Tadjine, M. Boucherit
The paper describes a vector fault tolerant control of squirrel cage induction machines (IM). The field oriented control (FOC) was combined to robust sliding mode control (SMC). This last is a technique to adjust feedback by previously defining a surface. The controlled state variables will be forced to move on this surface, then the behavior of the machine slides to the desired equilibrium point. We have taken the stator interturn fault, which is the most frequently encountered in practice. An analytical method for the modelling of this fault has been presented including space harmonics effect. This method is based on the calculation of the magnetic field distribution through the machine air-gap. The obtained model is less complicated to be implemented for condition monitoring or to validate fault tolerant control algorithms. Simulation results show, on the one hand that the proposed control scheme provides highperformance dynamic characteristics, and on the other hand the applicability and the tolerance of this control.
{"title":"Vector fault tolerant control of induction motor drives subject to stator interturn faults","authors":"D. Kouchih, R. Hachelaf, N. Boumalha, M. Tadjine, M. Boucherit","doi":"10.1109/EPEPEMC.2014.6980619","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980619","url":null,"abstract":"The paper describes a vector fault tolerant control of squirrel cage induction machines (IM). The field oriented control (FOC) was combined to robust sliding mode control (SMC). This last is a technique to adjust feedback by previously defining a surface. The controlled state variables will be forced to move on this surface, then the behavior of the machine slides to the desired equilibrium point. We have taken the stator interturn fault, which is the most frequently encountered in practice. An analytical method for the modelling of this fault has been presented including space harmonics effect. This method is based on the calculation of the magnetic field distribution through the machine air-gap. The obtained model is less complicated to be implemented for condition monitoring or to validate fault tolerant control algorithms. Simulation results show, on the one hand that the proposed control scheme provides highperformance dynamic characteristics, and on the other hand the applicability and the tolerance of this control.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124552871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980548
J. Rąbkowski, S. Piasecki, M. Kazmierkowski
This paper describes a design procedure of a three-phase AC/DC converter with special focus on semiconductors: paralleled SiC MOSFETs and SiC Schottky diodes. The converter is aimed to operate as a 14kVA Support Converter (SC) for the 55kVA AC drive system. The SC acts as active parallel filter during normal operation of the drive and is also capable to return part of the regenerative breaking energy to the supply grid. Initial calculations of power losses conducted with Matlab are verified by simulations in SABER software. Laboratory model designed on the base of calculations and simulations was tested with special attention to power losses measurements. Total efficiency of the AC/DC converter (including LC filter and gate drivers) measured during inverter operation is on the level of 98.8% at switching frequency of 40kHz.
{"title":"Design of a three-phase AC/DC converter with paralleled SiC MOSFETs","authors":"J. Rąbkowski, S. Piasecki, M. Kazmierkowski","doi":"10.1109/EPEPEMC.2014.6980548","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980548","url":null,"abstract":"This paper describes a design procedure of a three-phase AC/DC converter with special focus on semiconductors: paralleled SiC MOSFETs and SiC Schottky diodes. The converter is aimed to operate as a 14kVA Support Converter (SC) for the 55kVA AC drive system. The SC acts as active parallel filter during normal operation of the drive and is also capable to return part of the regenerative breaking energy to the supply grid. Initial calculations of power losses conducted with Matlab are verified by simulations in SABER software. Laboratory model designed on the base of calculations and simulations was tested with special attention to power losses measurements. Total efficiency of the AC/DC converter (including LC filter and gate drivers) measured during inverter operation is on the level of 98.8% at switching frequency of 40kHz.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"23 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130900482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980522
Mamadou Oury Fatoumata Diallo, S. Youssef, H. Gualous, M. Camara, B. Dakyo
This paper presents the control strategy of the permanent magnet synchronous generator (PMSG) destined to Raz Blanchard's tidal turbine application. Used PMSG presents a rated power of 2 MW connected to a tidal turbine with a radius of 10 m. The produced energy is injected in electrical grid with line to line RSM voltage of 20kV-50Hz. The used converter for energy management is based on back-to-back configuration. Proposed control strategies are implemented in Matlab/Simulink software for system simulations. The simulations are done using the tidal current magnitude obtained from hydrodynamic model, and obtained results are presented and analyzed.
{"title":"Permanent magnet synchronous generator for tidal turbine application in Raz Blanchard — Modeling and control strategy","authors":"Mamadou Oury Fatoumata Diallo, S. Youssef, H. Gualous, M. Camara, B. Dakyo","doi":"10.1109/EPEPEMC.2014.6980522","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980522","url":null,"abstract":"This paper presents the control strategy of the permanent magnet synchronous generator (PMSG) destined to Raz Blanchard's tidal turbine application. Used PMSG presents a rated power of 2 MW connected to a tidal turbine with a radius of 10 m. The produced energy is injected in electrical grid with line to line RSM voltage of 20kV-50Hz. The used converter for energy management is based on back-to-back configuration. Proposed control strategies are implemented in Matlab/Simulink software for system simulations. The simulations are done using the tidal current magnitude obtained from hydrodynamic model, and obtained results are presented and analyzed.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130934342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980647
H. Djeghloud, M. Larakeb, A. Bentounsi, Y. Terriche, D. Kerdoun
Practical and simulation studies of a hybrid system of series active power filter and shunt passive filter is presented in this two-part paper. Whereas part 1 concerns dimensioning, designing and starting up of the shunt passive filter, this second part is dedicated to dimensioning, conceiving and implementing of the series active filter. The works consist mainly to realize a two-level full bridge voltage inverter based on IGBT's. The respective overvoltage circuit and average control circuit are also conceived. The control is conducted in an open loop, the reference signals are identified using the p-q theory concept, and for launching the gating signals, the carrier-based PWM method is employed. The implementation of the whole system gave satisfactory results and improved the quality of power in the main utility side.
{"title":"Laboratory implementation of a hybrid series active power filter system part II: Series active filter designing","authors":"H. Djeghloud, M. Larakeb, A. Bentounsi, Y. Terriche, D. Kerdoun","doi":"10.1109/EPEPEMC.2014.6980647","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980647","url":null,"abstract":"Practical and simulation studies of a hybrid system of series active power filter and shunt passive filter is presented in this two-part paper. Whereas part 1 concerns dimensioning, designing and starting up of the shunt passive filter, this second part is dedicated to dimensioning, conceiving and implementing of the series active filter. The works consist mainly to realize a two-level full bridge voltage inverter based on IGBT's. The respective overvoltage circuit and average control circuit are also conceived. The control is conducted in an open loop, the reference signals are identified using the p-q theory concept, and for launching the gating signals, the carrier-based PWM method is employed. The implementation of the whole system gave satisfactory results and improved the quality of power in the main utility side.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115872461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980576
C. Pavlitov, T. Tashev, A. Dimitrov, Yassen Gorbounov, R. Rusinov
This paper deals with rotor position estimation of switched reluctance motors (SRM). The estimation method can be applied in SRM sensorless control of position speed and torque controllers. The implementation suggested is based on a real time adaptive filter. The measured variables are supply voltage and stator currents. These currents are used repeatedly for rotor position estimation by using linear adaptive filter which time constant is adjusted to the speed of the rotor. The result of this estimation is a rather precise and convenient rotor angle determining device for SRM sensorless control electrical drives.
{"title":"Rotor position estimation for a sensorless switched reluctance motor drive with the aid of real time adaptive filter","authors":"C. Pavlitov, T. Tashev, A. Dimitrov, Yassen Gorbounov, R. Rusinov","doi":"10.1109/EPEPEMC.2014.6980576","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980576","url":null,"abstract":"This paper deals with rotor position estimation of switched reluctance motors (SRM). The estimation method can be applied in SRM sensorless control of position speed and torque controllers. The implementation suggested is based on a real time adaptive filter. The measured variables are supply voltage and stator currents. These currents are used repeatedly for rotor position estimation by using linear adaptive filter which time constant is adjusted to the speed of the rotor. The result of this estimation is a rather precise and convenient rotor angle determining device for SRM sensorless control electrical drives.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127030124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980608
Tin Bariša, Mihovil Bartulovic, Goran Zuzic, Š. Ileš, J. Matuško, F. Kolonic
In this paper nonlinear Model Predictive Control of a tower crane based on reference shaping is proposed. MPC controller is used to calculate optimal reference for the inner control loop of the tower crane. The main objectives that the MPC controller needs to fulfill are tracking the reference position, suppressing the payload oscillations while satisfying operational constraints of the crane. The inner loop consists of P position controller and PI velocity controller which is common in industrial applications and easily implementable in standard frequency converters used in the cranes. The proposed approach is verified through simulation and experimental test on laboratory model of a 3D tower crane.
{"title":"Nonlinear predictive control of a tower crane using reference shaping approach","authors":"Tin Bariša, Mihovil Bartulovic, Goran Zuzic, Š. Ileš, J. Matuško, F. Kolonic","doi":"10.1109/EPEPEMC.2014.6980608","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980608","url":null,"abstract":"In this paper nonlinear Model Predictive Control of a tower crane based on reference shaping is proposed. MPC controller is used to calculate optimal reference for the inner control loop of the tower crane. The main objectives that the MPC controller needs to fulfill are tracking the reference position, suppressing the payload oscillations while satisfying operational constraints of the crane. The inner loop consists of P position controller and PI velocity controller which is common in industrial applications and easily implementable in standard frequency converters used in the cranes. The proposed approach is verified through simulation and experimental test on laboratory model of a 3D tower crane.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127219979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980531
Ammar Akhlaq, Jameel Ahmad, Ayesha Umber
This paper describes the implementation of biologically inspired self-reconfigurable control system for a multivariable hexapod robot having gait switching ability. It focuses on the control; based on forward and inverse kinematics for systematic locomotion and navigation of robot. Electronic system have the capabilities to measure physical variables. Force and pressure sensors are mounted on each end of the leg to provide the necessary sense of touch. The paper also explains the reconfiguration ability of the robot in case of any damage to its leg and its capacity to change the walking pattern according to the malfunction caused. The system implementation using multiple microcontrollers in master-slave configuration to produce and control 18 DOF is also shown in the paper.
{"title":"Biologically inspired self-reconfigurable hexapod with adaptive locomotion","authors":"Ammar Akhlaq, Jameel Ahmad, Ayesha Umber","doi":"10.1109/EPEPEMC.2014.6980531","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980531","url":null,"abstract":"This paper describes the implementation of biologically inspired self-reconfigurable control system for a multivariable hexapod robot having gait switching ability. It focuses on the control; based on forward and inverse kinematics for systematic locomotion and navigation of robot. Electronic system have the capabilities to measure physical variables. Force and pressure sensors are mounted on each end of the leg to provide the necessary sense of touch. The paper also explains the reconfiguration ability of the robot in case of any damage to its leg and its capacity to change the walking pattern according to the malfunction caused. The system implementation using multiple microcontrollers in master-slave configuration to produce and control 18 DOF is also shown in the paper.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124089056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/EPEPEMC.2014.6980596
Y. Onal, O. Gerek, D. G. Ece
Hilbert Huang Transform, which was suggested by Huang and improved by Flandrin and his group, is a new signal processing method. The analysis of nonlinear and non stationary signals can use HHT. This paper deals with the use of a HHT to detect and analyze voltage harmonics and flickers. In this method, the recorded harmonic signal and flicker signal are decomposed into Intrinsic Mode Functions using the Emprical Mode Decomposition. The frequency and amplitude of voltage harmonics and voltage flickers are obtained of IMF components by using Hilbert Transform HT. The clear success of EMD in defining envelope variations of a sinusoidal waveform has been the main motivation for the adoption of HHT in harmonic and flicker analysis. Simulations are performed over waveforms including voltage harmonics and voltage flickers. The waveforms are selected as pure sinusoids. Simulation results show that the suggested methodology constitutes a credible way to analyze voltage harmonics and voltage flickers.
{"title":"Detection of voltage flicker and voltage harmonic using Hilbert Huang Transform","authors":"Y. Onal, O. Gerek, D. G. Ece","doi":"10.1109/EPEPEMC.2014.6980596","DOIUrl":"https://doi.org/10.1109/EPEPEMC.2014.6980596","url":null,"abstract":"Hilbert Huang Transform, which was suggested by Huang and improved by Flandrin and his group, is a new signal processing method. The analysis of nonlinear and non stationary signals can use HHT. This paper deals with the use of a HHT to detect and analyze voltage harmonics and flickers. In this method, the recorded harmonic signal and flicker signal are decomposed into Intrinsic Mode Functions using the Emprical Mode Decomposition. The frequency and amplitude of voltage harmonics and voltage flickers are obtained of IMF components by using Hilbert Transform HT. The clear success of EMD in defining envelope variations of a sinusoidal waveform has been the main motivation for the adoption of HHT in harmonic and flicker analysis. Simulations are performed over waveforms including voltage harmonics and voltage flickers. The waveforms are selected as pure sinusoids. Simulation results show that the suggested methodology constitutes a credible way to analyze voltage harmonics and voltage flickers.","PeriodicalId":325670,"journal":{"name":"2014 16th International Power Electronics and Motion Control Conference and Exposition","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127304079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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